bio topic 6 : ch8 flashcards

genes:

unit of information encoded in the sequence of nucleotide basis in DNA; encodes an RNA or protein product

gene expression:

multistep process of converting information in a gene into an RNA or protein product.

transcription:

RNA synthesis; process in which a gene is copied into RNA form

Ribosomal RNA:

RNA component of ribo-somes.

Transfer RNA (tRNA):

RNA that delivers amino acids to a ribosome during translation.

messenger RNA (mRNA):

RNA that carries protein-building instructions.

translation:

Process by which a polypeptide chain is assembled according to the protein-building information in an mRNA.

RNA polymerase:

Enzyme that carries out transcription (RNA synthesis).

promoter:

In DNA, special sequence of nucleotide bases that functions as a binding site for RNA polymerase; site where transcription begins.

introns:

Gene segment that intervenes between exons and is removed from a new RNA during post-transcriptional modification.

exons:

Gene segment that remains in an RNA after post-transcriptional modification.

codons:

Three-nucleotide unit of information in an mRNA; the order of the three bases determines the instruction. Most specify particular amino acids.

genetic code:

Complete set of sixty-four codons

anticodon:

In a tRNA, set of three nucleotides that base-pairs with an mRNA codon.

base-pair substitution:

Type of mutation in which a single base pair changes.

deletion:

Type of mutation in which one or more nucleotides are lost from DNA.

insertion:

Type of mutation in which one or more nucleotides are inserted into DNA.

transcription factors:

Regulatory protein that influences transcription by binding directly to DNA.

master regulator:

Gene whose expression triggers a gene expression cascade that ultimately changes cells in a lineage from one type to other, more differentiated types.

knockout:

Technique of introducing a mutation that disables expression of a gene in an organism.

Barr body:

Condensed, inactivated X chromosome in a body cell of a female mammal (the other X chromosome is active).

epigenetic:

Refers to potentially heritable modifications to DNA that affect gene expression without changing the DNA sequence.